I need help w/ physics homework

>>160983
Let the axis be [N, W]

Average: (100s*[-1m/s,0] + 50s[0,1m/s] + 150s[1m/s,0] + 75s[-1/√2m/s,1/√2m/s] + 25s[-1m/s, 0])/400s = (3√2-2)/32 m/s S, (3√2-2)/32 m/s W = 0.0701m/s S, 0.258m/s W
or
(net displacement)/time = (100m*[-1,0] + 50m[0,1] + 150m[1,0] + 75m[-1/√2,1/√2] + 25m[-1, 0])/400s = 0.0701m/s S, 0.258m/s W

According to the answer at the back it is 0.27ms-1 at 255 degrees?? I have no clue how to achieve that answer though

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46KB, 500x463px

>>160990

√(0.0701^2 + 0.258^2) = 0.267 m/s
arctan(-.258/-.0701) + 180 = 254.7993896 deg off North CLOCKWISE

>>160990
velocity is directional so instead of adding up how much you have moved, you want to figure out how far away you ended up from where you started

try drawing out the entire path and making an arrow from where you started to where you ended up, this distance is what you want to find

you can think of a movement south as a negative movement north and vice versa so when you move 100 meters south, then 150 meters north, then 25 meters south again in total you have moved 25 meters north

for the 75 meters SW draw a right triangle with a hypotenuse of 75, it will be much easier to break it down into two vectors, one moving south and one moving west. so solve for a and b assuming that angle A and angle B are both 45 degrees, this is going to give you a nasty answer of 75 over root 2 for both

once you have found the total distance moved west and the total distance moved south make a right triangle and solve for the hypotenuse, with this distace you can divide by the time and convert to m/s to get an answer close to the one given in the book, to get the angle you can use the law of sines and inverse trig functions to find the angle but keep in mind what direction your angle is off of